I use both a cd player(Cambridge D500SE) and a tuntable(technics). I honestly can say that my mint condition "House of the Holy" LP sounds better than the cd version. At the same time I find many of the digitaly remastered Greatful Dead cd's sound quite good. I think a well recorded cd played on a good cd player can sound quite good. At the same time $5 LP's on my $50 turntabe also sound quite good.
I think if one were to compare a $500 turntable to a $500 cd player it would come down to how well the recordings were done. That is how well the analog signal was converted to digital and put on the cd and the condition of the LP.

As for SACD and DVD-Audio, I hope one or the other catches on and people decide to sell their records and cd's for cheap.